by Dr Caroline Hendry (PhD Developmental Biology)
There’s no denying it, we live a fast-paced life. There’s everything from instant meals to instant tan and even instant drugs. We expect results, stat. So when it comes to falling asleep, it’s no wonder that a little tossing and turning has a lot of Australians reaching for a quick fix. One of the most popular sleeping drugs for adults is melatonin, and an increasing number of parents are also giving it to their children. But do we really know what we’re doing? And is it safe?
Probably not, suggests Professor David Kennaway, a specialist in circadian sleep cycles in the school of Pediatrics and Reproductive Health, University of Adelaide.
While there are some situations where the benefits of pharmacological intervention outweigh the risks, such as Delayed Sleep Phase Syndrome or Autistic Spectrum Disorder, for most normal children a nightly dose of melatonin may do more harm than good.
In his recent Review article, Prof Kennaway discusses the safety issues surrounding the use of melatonin in both adults and children. The evidence is alarming: not only is melatonin being prescribed to children when it is not registered for use in children anywhere in the world, but there is a long history of studies in animals that show that melatonin also interferes with the reproductive, circulatory and metabolic systems. Perhaps most worryingly, there are no solid, convincing clinical studies to analyse the long term safety of melatonin use in either adults or children.
In this special report, The Baby Sleep Company (TBSC) caught up with Prof. Kennaway (DK) to discuss the use of melatonin in children to find out if it’s really as unsafe as it sounds. Here’s what he had to say:
TBSC: So what is melatonin and why do people take it?
DK: Melatonin is a hormone that is produced in the brain, in a structure called the pineal gland. The amount that is made and when it is released is controlled very tightly. It enters the bloodstream starting in the early evening and continues until around breakfast time, in other words while we sleep. People take melatonin to help them fall asleep more quickly, typically when moving between time zones or if they have been diagnosed with a clinical sleep disorder such as Delayed Sleep Phase Syndrome.
TBSC: So if melatonin is produced in the brain, how does it affect other systems in our body?
DK: Because melatonin is a hormone, it targets receptors to bring about its actions. These receptors are located in a wide range of tissues that are unrelated to sleep, such as the pancreas, the cardiovascular system, the adrenal gland, the ovaries, breasts, etc. The role of melatonin in these tissues is still under active investigation, but it makes sense that interfering with melatonin levels overall would interfere with these tissues too.
TBSC: Is melatonin currently registered for use in children in Australia?
DK: Melatonin is not registered for use in children in any jurisdiction in the world.
When prescribed for children in Australia and elsewhere, it is being done so “off label”. In Australia the registered product Circadin is for “…the short term treatment of … insomnia … in patients who are aged 55 or over.” (source Australian Register of Therapeutic Goods).
TBSC: In your opinion, what is the most concerning possible side effect of melatonin use in children?
DK: The most concerning possible side effect of melatonin relates to interference in the reproductive system of children if it is taken over a long period prior to puberty.
TBSC: How likely do you think it is that children who take melatonin regularly might undergo changes to their reproductive system? Where's the evidence?
DK: Animal research over the last 50 years has highlighted the role of melatonin in a wide range of processes including the reproductive system. In the animal kingdom, the release of melatonin is used to time the onset of puberty and synchronise the breeding season of many species.
TBSC: So it has clearly been shown to interfere with the reproductive system in a wide range of animals.
DK: Right. In fact, my team developed a type of melatonin that alters the breeding season of sheep and goats. It is still a registered and effective Veterinary drug used internationally.
TBSC: That’s really scary! If the evidence is so clear, why isn’t it illegal to give melatonin to children?
DK: The biggest drug regulator in the world is the US Food and Drug Administration (FDA). They insist on tough clinical trials and safety data before a drug can be prescribed and sold. Problem is, in the US melatonin has not been evaluated or controlled by their FDA because it is deemed as a “dietary supplement” and not a drug.
TBSC: So melatonin is flying under the radar, so to speak?
DK: Yes. It is most unlikely that melatonin, if it had been evaluated by the FDA, would ever have been cleared for use in children. In fact, the registered melatonin Circadin, which is sold in Australia, specifically states in the Product Information documentation that “Circadin is not recommended for use in children and adolescents below 18 years of age due to insufficient data on safety and efficacy.”
TBSC: What does that mean, insufficient data?
DK: All of the studies on melatonin in children have been small and not designed to evaluate long term side effects. They did not include any of the appropriate assessments and in some cases while concluding that there were no adverse effects, the authors failed to actually provide details of what was evaluated! So because these studies are flawed, it’s not really possible to draw any solid conclusions with regard to the safety of melatonin. That’s what insufficient data means.
TBSC: Is there ever a situation where it's necessary to use melatonin in children?
DK: Severe neurological disorders in children are often accompanied by sleep problems that are extremely difficult to deal with. It may be appropriate to try melatonin in such cases. However, one must remember that melatonin itself has not been shown to maintain sleep; it is mainly used to advance the onset of sleep timing in clinically diagnosed Delayed Sleep Phase Syndrome. So melatonin might get you to sleep a little quicker, but it won’t keep you asleep the same way a sleeping pill would.
TBSC: What would you say to any parent currently giving or considering giving melatonin to their child?
DK: Firstly, if a child is currently being given melatonin to advance the time of sleep, the treatment should not be prolonged more than a month or two. Do not increase the dose if it does not appear to be working. While treating with melatonin, make sure that other sensible procedures around bed time are maintained, including maintaining a routine, keeping the bedroom dark at night and not letting the child sleep-in in the morning. If the sleeping problem recurs when the melatonin is stopped seek advice from a paediatrician.
If your child cannot get to sleep at a realistic, age appropriate time, seek advice from a paediatric sleep specialist, not a general practitioner. The paediatrician will have a number of approaches that do not involve popping pills. Melatonin should only be a last resort for intractable delayed sleep onset and then only used for a short period. Doctors and parents should remember that melatonin is not a sleeping pill and will not stop the child from waking or increase the time asleep.
Professor David Kennaway is an NHMRC Senior Research Fellow and Research Program Leader of the Circadian Physiology Group at the University of Adelaide. He is a member of the Australian Society for Medical Research and has authored over 150 peer-reviewed research articles on melatonin, sleep and reproduction. You can read more about Prof Kennaway here.
Want to know more? Here’s where you can get the original article: Kennaway, D.J. Potential safety issues in the use of the hormone melatonin in paediatrics. J Paediatr Child Health. 2015 Feb 3. doi: 10.1111/jpc.12840. [Epub ahead of print].
You can read more about Dr Caroline Hendry here
An extra note from Katie Forsythe (owner of The Baby Sleep Company)
When I asked Dr Hendry to write me an article about melatonin and its use with children neither of us had any idea that this information would be what she uncovered. When she sent me through her draft I was shocked by the information she was telling me. Shocked and, quite frankly, scared.
Scared because I myself have friends who use melatonin to help their children with Autism Spectrum Disorder (ASD) sleep. I worried that my own friends might think I was judging them for using this drug on their children.
I want to make it abundantly clear that we understand that in some cases the benefits far outweigh the risks, and that to tell a parent of a child who literally has only slept a handful of hours over three whole days that she shouldn’t try a treatment that might help is just cruel.
What I am concerned about is that I see many many people who say that they’ve tried melatonin for their child. They have been prescribed melatonin by their doctors and in most cases were not told of this scientific information. They were not even informed that they were being prescribed a medicine off-label (off-label means prescribing a drug for a condition that it wasn’t intended for), let alone that it is not currently approved for use for children in any jurisdiction in the world.
We are not judging people for using melatonin, only encouraging people to ask questions when prescribed melatonin.
You might also be interested in reading one of our other recent articles:
If you would like personalised help with any sleep issue for a child, newborn to 5 years, contact The Baby Sleep Company today on 0457 473 725 or click here to send us an email.